/*!	 synfig/rendering/opengl/task/tasksurfaceresamplegl.cpp
**	 TaskSurfaceResampleGL
**
**	......... ... 2015 Ivan Mahonin
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifdef USING_PCH
#	include "pch.h"
#else
#ifdef HAVE_CONFIG_H
#	include <config.h>
#endif

#ifndef _WIN32
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#endif

#include <synfig/general.h>
#include <synfig/localization.h>

#include "tasksurfaceresamplegl.h"

#include "../internal/environment.h"
#include "../surfacegl.h"

#endif

using namespace synfig;
using namespace rendering;

bool
TaskSurfaceResampleGL::run(RunParams & /* params */) const
{
    gl::Context::Lock lock(env().context);

    SurfaceGL::Handle a =
        SurfaceGL::Handle::cast_dynamic(sub_task()->target_surface);
    SurfaceGL::Handle target =
        SurfaceGL::Handle::cast_dynamic(target_surface);

    // TODO: gamma

    Vector rect_size = get_source_rect_rb() - get_source_rect_lt();
    Matrix bounds_transfromation;
    bounds_transfromation.m00 = fabs(rect_size[0]) > 1e-10 ? 2.0 / rect_size[0] : 0.0;
    bounds_transfromation.m11 = fabs(rect_size[1]) > 1e-10 ? 2.0 / rect_size[1] : 0.0;
    bounds_transfromation.m20 = -1.0 - get_source_rect_lt()[0] * bounds_transfromation.m00;
    bounds_transfromation.m21 = -1.0 - get_source_rect_lt()[1] * bounds_transfromation.m11;

    Matrix matrix = transformation * bounds_transfromation;

    // prepare arrays
    Vector k(target->get_width(), target->get_height());
    Vector d(matrix.get_axis_x().multiply_coords(k).norm().divide_coords(k).mag() / matrix.get_axis_x().mag(),
             matrix.get_axis_y().multiply_coords(k).norm().divide_coords(k).mag() / matrix.get_axis_y().mag());
    d *= 4.0;
    Vector coords[4][3];

    for (int i = 0; i < 4; ++i) {
        coords[i][2] = Vector(i % 2 ? 1.0 : -1.0, i / 2 ? 1.0 : -1.0).multiply_coords(Vector(1.0, 1.0) + d);
        coords[i][0] = matrix.get_transformed(coords[i][2] * 0.5 + Vector(0.5, 0.5));
        coords[i][1] = (coords[i][2] + Vector(1.0, 1.0)) * 0.5;
    }

    Vector aascale = d.one_divide_coords();

    gl::Framebuffers::FramebufferLock framebuffer = env().framebuffers.get_framebuffer();
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, framebuffer.get_id());
    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, target->get_id(), 0);
    glViewport(
        get_target_rect().minx,
        get_target_rect().miny,
        get_target_rect().maxx - get_target_rect().minx,
        get_target_rect().maxy - get_target_rect().miny);
    env().context.check();

    glBindTexture(GL_TEXTURE_2D, a->get_id());
    glBindSampler(0, env().samplers.get_interpolation(interpolation));
    env().context.check();

    gl::Buffers::BufferLock buf = env().buffers.get_array_buffer(coords);
    gl::Buffers::VertexArrayLock va = env().buffers.get_vertex_array();
    env().context.check();

    glBindVertexArray(va.get_id());
    glBindBuffer(GL_ARRAY_BUFFER, buf.get_id());
    glEnableVertexAttribArray(0);
    glEnableVertexAttribArray(1);
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(0, 2, GL_DOUBLE, GL_TRUE, sizeof(coords[0]), (const char*)buf.get_pointer() + 0 * sizeof(coords[0][0]));
    glVertexAttribPointer(1, 2, GL_DOUBLE, GL_TRUE, sizeof(coords[0]), (const char*)buf.get_pointer() + 1 * sizeof(coords[0][0]));
    glVertexAttribPointer(2, 2, GL_DOUBLE, GL_TRUE, sizeof(coords[0]), (const char*)buf.get_pointer() + 2 * sizeof(coords[0][0]));
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    env().context.check();

    env().shaders.antialiased_textured_rect(interpolation, aascale);
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    env().context.check();

    glDisableVertexAttribArray(0);
    glDisableVertexAttribArray(1);
    glDisableVertexAttribArray(2);
    glBindVertexArray(0);
    env().context.check();

    glBindSampler(0, 0);
    glBindTexture(GL_TEXTURE_2D, 0);
    env().context.check();

    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
    env().context.check();

    return true;
}